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The invention pertains to a hoisting platform system, particularly to a hoisting platform system that is used in the construction of high rise buildings. There are various power cranes and platform hoists that are known and are useful in the construction of high rise buildings while under construction. One such crane is known as an aerial platform crane or as a platform crane. This crane is only useful to place building material on top of the rising building or in conjunction with outrigger platforms that jut out from the various concrete slabs already constructed. The load that has been picked up by the platform crane is lowered on to such a platform and the material is then moved inside of the building by hand or by various moving implements such as dollies, hand trucks etc.
Another type of crane is movable on the ground and can be placed at different locations. Such a crane has an extendible boom that can be swung to various locations and again operates in conjunction with the above mentioned outrigger platforms.
Still another hoisting crane is known as the xe2x80x9cbuck hoistxe2x80x9d which has a static tower attached to the building with the tower having a pulley at the top over which a cable will run which in turn is attached to a cage. The cage can transport personal as well as material. The operator is located on the ground and is operating a winch which in turn will lift or lower the cage on command.
All of the above mentioned cranes have the disadvantage in that the operator of any of the cranes is always located remote from where the load is to be deposited on any of the concrete slabs at any height of the building. This fact involves a lot of guess work or another person to signal when exactly the descending load is in place or when the cage has reached a correct position. Another disadvantage is that the cranes are always busy and there is always a time lag between and when a particular load can be transported. Some of the cranes can only be operated under electric power which limits the load capacity.
U.S. Pat. No. 683,624 shows a crane assembly that operates inside a building under construction including a tower structure. A cable runs over two adjacent pulleys on top of the tower and the cable ends are attached to two hoisting platforms that operate in tandem.
U.S. Pat. No. 2,364,224 discloses a hoisting means which can be quickly and easily attached to a building window structure and can be employed for lifting articles such as storm windows up or down from an upper story.
U.S. Pat. No. 3,827,744 illustrates a hoisting cage that can contain various building materials to be lifted to any higher floors. The cage can be lifted by a tower crane or by a mobile crane on the ground. The cage has a ramp plate that can be lowered onto the concrete slab so that the load can be rolled out of cage and onto the concrete slab.
U.S. Pat. No. 3,876,099 discloses equipment that is useful for delivering materials to elevated floors of a building under construction. The equipment includes a frame adapted to be lifted by a construction crane having an overhead cable. The frame has bars for engaging a building floor to position the frame against the side of the building. The bottom of the frame or cage has a plurality of rollers that are instrumental in helping the load to be moved from the frame to the concrete slab.
U.S. Pat. No. 5,575,356 illustrates a platform hoist that is guided in two parallel and vertical support beams. The platform can be guided by wheels in slotted support beams. The wheels allow to load to be rolled into the building and onto the concrete slab once a predetermined height of a floor is reached.
An object of the invention is to simplify the delivering of the building materials in a high rise building under construction. This is accomplished by supporting two I-beams in parallelism to each other on a concrete slab of a building. A moving platform can move into the building with a load thereon or out of the building to receive a new load. The winch and the power supply for the winch to operate a hoisting cable is located on the same floor where the I-beams and the moving platform is located. In this manner, the winch cable can be lowered to the ground to pick up a new load while the just delivered load can be unloaded inside the building. This will shorten the waiting period of other loads to be lifted considerably. It is also possible to service lower floors provided other I-beams are located as outriggers on the lower floors. This is possible because once the moving platform has moved inside the building, there is no obstruction between the I-beams to hinder further operations. All of the necessary equipment and the various elements of the hoisting platform can easily be assembled and disassembled and moved to a different location. The hoisting power is preferably derived from a hydraulic power supply because of its superior energy force although electric power can be used too. The power supply is generated in the same location where the winch is located such as a diesel engine driving a hydraulic pump or an electric generator. Another advantage of the above described hoisting platform is that the operator is in close proximity to where the loads are to be deposited, whereby the operator has direct eye contact with the activities at their most critical moments.